Conventional sealing assemblies are employed in a wide variety of environments and settings, such as for example, in mechanical apparatuses, to provide a fluid-tight seal. The sealing assemblies are usually positioned about a rotating shaft or rod that is mounted in and protrudes from a stationary mechanical housing.
A conventional sealing assembly generally comprises a sealing element formed of an elastomeric material and a spring or other resilient biasing element for biasing the sealing element against a rotating shaft. The biasing element biases the sealing element into sealing engagement with the shaft to form a fluid-tight seal.
However, such sealing assemblies suffer from a number of deficiencies and disadvantages. For example, the spring is typically exposed to the internal or process fluid of the mechanical apparatus being sealed, which can potentially degrade the spring, potentially leading to the failure of spring. In addition, springs and other movable biasing elements tend to lose their resilient biasing characteristics over time, impairing the efficiency of the seal.
Another drawback of conventional sealing assemblies is the poor wear characteristics of the elastomeric sealing elements. As the sealing elements wear, the amount of radial sealing force provided by the sealing element against the shaft decreases, resulting in a corresponding decrease in the sealing effectiveness of the sealing elements. This expected degradation in sealing performance necessitates frequent monitoring, replacement and/or adjustment of the sealing elements. The replacement and adjustment process thus requires frequent periods of down time for the system employing the seal assembly, which reduces overall system sealing efficiency and hence increases costs.
Other and more specific objects of this invention will in part be obvious and in part be evident from the drawings and description which follow.